California’s drought emergency woes have worsened, with a shortage on the Colorado River next year becoming increasingly likely. Odds of a shortage rose from 33 percent to 50 percent from April 1 to May 1, Metropolitan Water District, Southern California’s largest water wholesaler, said Monday.

Also Monday, a Metropolitan committee also unsuccessfully considered a proposal to spend an extra $150 million on water conservation projects, such as paying to replace grass with low water-use landscaping. The committee unexpectedly deadlocked, with some members, including San Diego representatives, objecting to the cost. The full Metropolitan board will take up the proposal Tuesday.

Southern California get nearly all of its water from the Colorado and from Northern California. Both sources are severely strained. This year, Metropolitan is getting just 20 percent of contracted supplies from Northern California.

CALIFORNIA DROUGHT

On the Colorado, Lake Mead, the reservoir with the largest capacity in the United States, is 38 percent full, the lowest since it was first filled in the 1930s. So any shortage of Colorado River water would be especially painful. The agency supplies 19 million people in Southern California, including San Diego County.

Metropolitan’s estimate of a Colorado shortage is unofficial, with official numbers expected next week, said Bob Muir, a Metropolitan spokesman.

On April 1, Gov. Jerry Brown ordered a 25 percent reduction in urban use of potable water, starting in June and ending February. Brown acted after the Sierra Mountains snowpack, which feeds rivers and reservoirs, was found to be just 5 percent of average.

Snowmelt is also vital to the Colorado River basin, feeding the tributaries that feed into the river. And unlike the Sierras, where very little precipitation occurs during summer, about one-third of the precipitation in the Upper Colorado basin, falls from May through September. (The upper basin is mainly Wyoming, Utah and Colorado). So an especially dry summer would make a shortage more likely.

And Metropolitan’s own storage is beginning to get low. At the end of 2012, Metropolitan had dry-year storage of about 2.7 million acre-feet. Two years later, that storage had dropped to 1.2 million acre-feet. If trends continue, by the end of 2015 Metropolitan could have just 730,000 acre-feet of dry-year storage. This doesn’t include more than 600,000 acre-feet of emergency storage Metropolitan hopes it won’t have to tap.

If there is a Colorado River shortage, Metropolitan stands to lose first because it is low on the priority system of California’s water rights, said Keith Lewinger, a Metropolitan director who represents the San Diego County Water Authority. The authority, which often spars with Metropolitan, buys about half its water from the district.

The rest of the Water Authority’s supply comes from the Imperial Valley. This source won’t be affected by a shortage because the farmers supplying the water have senior rights.

“If Palo Verde (Irrigation District in Riverside County) goes over 420,000 acre-feet, for every acre-foot, Met loses an acre-foot,” Lewinger said. “Right now, the Colorado River Board is projecting, as of the beginning of May, that this year, they’re going to go over by 70,000 acre-feet. They’re going to use 490,000 acre-feet. So that’s 70,000 acre-feet that Metropolitan is counting on, that they’re not going to get, based on current projections.”

To minimize water use, Metropolitan’s Water Planning and Stewardship Committee considered a proposal to greatly expand an existing program that pays those with lawns if they replace them with less thirsty landscaping, such as low-water-use plants or artificial turf. Metropolitan now pays $2 a square foot for property owners who take part. The program was originally funded with $100 million, of which $77 million is already spent.

The proposal would add an extra $150 million, which would be spent during fiscal year 2015/2016. Metropolitan’s fiscal year begins July 1.

Lewinger strongly protested the program’s cost at the committee meeting, saying it would not only drive up rates, but was not needed, because after Gov. Brown’s declaration, people know that lawns are the most likely use that can be cut to meet the mandated reductions.

Lewinger was joined in his criticisms by committee members from other parts of Metropolitan’s service area.

“I don’t think we can keep throwing money at this. It’s not sustainable,” said Linda Ackerman, who represents Municipal Water District of Orange County on the MWD board.

Michele Martinez, who represents Santa Ana, said rate increases needed to pay for the program would hurt city’s residents, who use a relatively low 76 gallons per person per day.

“Every little increase is going to hurt our residents,” Martinez said. “These are people who don’t make more than $25,000 a year.”

Metropolitan’s board is scheduled to meet at noon Tuesday at its headquarters, 700 N. Alameda St. next to Los Angeles Union Station.